Paving nightmare
Discussion
So I am trying to lay some paving slabs in the garden - I've already done a lot of the hard work in taking up the old slabs and putting in a base.
The slabs are indidian sandstone so all different thicknesses and the surfaces are not perfectly flat.
My difficulty is when I put the slab down initally I am finding it very difficult to get it at the right level (to match a brick course of my house) - once I start using a mallett to adjust levels of the falls - I can never get it right - either the slab doesn't move enough or if you hit it too much one way it buggers the level the opposite direction.
I have tried various mortar (sharp sand and cement) strengths (4 in 1 and now 6 in 1) and different water volumes from a dry mix to a wet mix. I found with the wet mix when I was using the mallett to hit the slab down it was eventually causing water to rise up.
I think I need to try and get the bed of mortar perfect before I put the slab on.
Any tips on how to resovle this before I throw the towel in?
The slabs are indidian sandstone so all different thicknesses and the surfaces are not perfectly flat.
My difficulty is when I put the slab down initally I am finding it very difficult to get it at the right level (to match a brick course of my house) - once I start using a mallett to adjust levels of the falls - I can never get it right - either the slab doesn't move enough or if you hit it too much one way it buggers the level the opposite direction.
I have tried various mortar (sharp sand and cement) strengths (4 in 1 and now 6 in 1) and different water volumes from a dry mix to a wet mix. I found with the wet mix when I was using the mallett to hit the slab down it was eventually causing water to rise up.
I think I need to try and get the bed of mortar perfect before I put the slab on.
Any tips on how to resovle this before I throw the towel in?
Don't use the 5 spots of mortar method for a start, they will be easier to lay , but it's not the correct way. Use a mix of 6 parts grit sand and 1 cement, slightly stiffer than a brick laying mix, if you know what that is. Using a brick trowel spread the mortar flat slightly lower than where the bottom of the flag will be using the brickwork, adjacent flags or your string lines as a guide. Then using your trowel put some 'furrows' into the mortar, like a farmer plowing a field. These will help you to tap down the flags to the correct level. You may end up with some 'lips' sticking up, don't panic these can't always be helped when using a riven flag. You will also still end up taking some flags up and relaying them, everyone does! Have a look here:
indian sandstone
laying riven flags
bond bridge
indian sandstone
laying riven flags
bond bridge
i had an extension last year and the builders laid a patio and path etc. bloody nightmare.
indian sandstone as per you, and they just didn't do the job right, different gaps, different angles, loose slabs (if yours are the same they are more like garden 'tiles' than slabs, not as thick as the council spec monsters they replaced) truth be told, at some point we'll probably have the lot redone.
they took up a whole run that was wonky, relaid some that formed a nice puddle outside the back door and I've had a few others reset where they wobble. but then it got to the point where the builder was telling me it was as good as he'd get them. he didn't do them, his two labourers did, suspect it was down to me negotiating hard on some of his prices....!
indian sandstone as per you, and they just didn't do the job right, different gaps, different angles, loose slabs (if yours are the same they are more like garden 'tiles' than slabs, not as thick as the council spec monsters they replaced) truth be told, at some point we'll probably have the lot redone.
they took up a whole run that was wonky, relaid some that formed a nice puddle outside the back door and I've had a few others reset where they wobble. but then it got to the point where the builder was telling me it was as good as he'd get them. he didn't do them, his two labourers did, suspect it was down to me negotiating hard on some of his prices....!
wolfracesonic said:
Don't use the 5 spots of mortar method for a start, they will be easier to lay , but it's not the correct way. Use a mix of 6 parts grit sand and 1 cement, slightly stiffer than a brick laying mix, if you know what that is. Using a brick trowel spread the mortar flat slightly lower than where the bottom of the flag will be using the brickwork, adjacent flags or your string lines as a guide. Then using your trowel put some 'furrows' into the mortar, like a farmer plowing a field. These will help you to tap down the flags to the correct level. You may end up with some 'lips' sticking up, don't panic these can't always be helped when using a riven flag. You will also still end up taking some flags up and relaying them, everyone does! Have a look here:
indian sandstone
laying riven flags
bond bridge
As above.indian sandstone
laying riven flags
bond bridge
Only thing I'd add is use feb or similar.
Use the correct dose or it'll kill the mix.
I realise you are a builder Spudler, and dot and dab is frowned on by many. However the OP isn't and he is and will struggle to lay Riven and uncalibrated flags the so called "correct" way.
I've laboured for a mate (stone mason) on dozens of patios over ten years. He always calls on me as He likes the way I mix and point, in particular he knows I will pay particular attention to really fill and compress the pointing before striking. It's poor pointing that gives dot and dab a bad name. Not once have we been called back to a job.
I've laboured for a mate (stone mason) on dozens of patios over ten years. He always calls on me as He likes the way I mix and point, in particular he knows I will pay particular attention to really fill and compress the pointing before striking. It's poor pointing that gives dot and dab a bad name. Not once have we been called back to a job.
wolfracesonic said:
I like his style:'Then came the imports. Stone flags could be quarried, hand-dressed, packed and shipped from what we used to refer to as "developing countries" [1] for a fraction of the price of British or Irish sourced stone. In some cases, the packs of flags were literally being used as ballast aboard ships delivering other goods to the EU. And the market was ready for it! The explosion of interest in 'lifestyle tv' had convinced many homeowners to carry outdoors those spending habits previously restricted to decor for inside the home, and we started hearing trendy garden designers spouting nonsense about making "outdoor rooms"[2], spending huge sums of money creating gardens and patios that might only be used for a couple of months of the year, but the market was primed and the people wanted to spend.
[1] - it seems they were primarily developing an interest in owning much of the infrastructure of allegedly developed countries
[2] - in some parts of the country, it is legal for anyone using this phrase to be smacked over the head with a spade'
dickymint said:
I realise you are a builder Spudler, and dot and dab is frowned on by many. However the OP isn't and he is and will struggle to lay Riven and uncalibrated flags the so called "correct" way.
I've laboured for a mate (stone mason) on dozens of patios over ten years. He always calls on me as He likes the way I mix and point, in particular he knows I will pay particular attention to really fill and compress the pointing before striking. It's poor pointing that gives dot and dab a bad name. Not once have we been called back to a job.
Dot and dab is just bad practice and on a natural stone like sandstone it can and often does show through where the hollow pockets are.I've laboured for a mate (stone mason) on dozens of patios over ten years. He always calls on me as He likes the way I mix and point, in particular he knows I will pay particular attention to really fill and compress the pointing before striking. It's poor pointing that gives dot and dab a bad name. Not once have we been called back to a job.
You'll need an individual bed for each due to their varying thickness unless they're honed.
Are you creating peaks and troughs in the mortar with the towel so it has somewhere to move to as you bed the slab?
I am using a full bed.
I am doing the troughs but maybe I need to make them a bit deeper.
I looked into using an additive but I thought I read that they were fine for bricklaying mortar but not so much for paving as the sharp sand makes less likely to work. I understand admix or whatever makes bricklaying mortar more workable so what can I use withsharp sand?
I am doing the troughs but maybe I need to make them a bit deeper.
I looked into using an additive but I thought I read that they were fine for bricklaying mortar but not so much for paving as the sharp sand makes less likely to work. I understand admix or whatever makes bricklaying mortar more workable so what can I use withsharp sand?
Gingerbread Man said:
dickymint said:
I realise you are a builder Spudler, and dot and dab is frowned on by many. However the OP isn't and he is and will struggle to lay Riven and uncalibrated flags the so called "correct" way.
I've laboured for a mate (stone mason) on dozens of patios over ten years. He always calls on me as He likes the way I mix and point, in particular he knows I will pay particular attention to really fill and compress the pointing before striking. It's poor pointing that gives dot and dab a bad name. Not once have we been called back to a job.
Dot and dab is just bad practice and on a natural stone like sandstone it can and often does show through where the hollow pockets are.I've laboured for a mate (stone mason) on dozens of patios over ten years. He always calls on me as He likes the way I mix and point, in particular he knows I will pay particular attention to really fill and compress the pointing before striking. It's poor pointing that gives dot and dab a bad name. Not once have we been called back to a job.
You'll need an individual bed for each due to their varying thickness unless they're honed.
Are you creating peaks and troughs in the mortar with the towel so it has somewhere to move to as you bed the slab?
Mojooo said:
I am using a full bed.
I am doing the troughs but maybe I need to make them a bit deeper.
Think about it, troughs in a flat bed is not much different to dot and dab - it allows you to tap the slab down to the desired position. A flat bed without troughs is almost impossible to get right with non calibrated stone (hard enough with), mortar will only compress so much no matter how hard you "bash it" You will get voids in a troughed flat bed just as well as you do with dot and dab.I am doing the troughs but maybe I need to make them a bit deeper.
Just try it
More recently Indian stone is machine cut and thinner than the old stuff that you were required to start with the thickest slab from the pack and match that level by using more mortar with the thinner ones. We lay on terram type membrane using a full outer bed of mortar and large dabs within each slab space. They are then tapped level using a rubber mallet. Some of the larger slabs can be concave and are returned to our supplier as they are no use for patios.
We use epoxy type pointing material rather than mortar for longevity and ease of use.
Some slabs are tile thin and when wet, patchy mortar is visible as dark markings on the surface but won't be noticed when dry.
We use epoxy type pointing material rather than mortar for longevity and ease of use.
Some slabs are tile thin and when wet, patchy mortar is visible as dark markings on the surface but won't be noticed when dry.
Right, I'll try and help here.
Tbh one thing I will say and it isn't aimed at you but more other paving people, builders etc is that many years ago stone took a certain knowledge to lay properly, now due to cost of it all everyone's a stone expert. It is IMO hard to lay and do it right.
The reason are
It's got a lot of tolerance in joint sizes, it can be un caliberated which tbh doesn't matter as your laying each slab individually on wet muck but it doesn't help. The surface is riven to the extent of a level doesn't really tell you you've done it right.
Here's what I would do or actually do
Set up some very taught string lines around the perimeter, if it's not square just square off a general main area first, then you can work off that once you've got some down. obviously start at the house and set your falls. This line is your finished patio level.....give or take a few mm.
To pull lines properly you need to bang something into the ground, a bit of 2x2 or what I use is those large steel pins used for temporary barriers etc.
You need enough fall, I can't remember what the actual recomended fall are off the top of my head but paving expert is your friend.
You want a cement bed depth of approx 75mm. Any less it's too thin, (unless going over concrete) any more and it's going to make life more difficult.
Mix sharp sand and cement to 5:1 or 4:1 or even 6:1
It needs to be wet enough to stick the slabs but not so wet that when you lay one and tap it down it starts swimming. Too dry and it won't be very pliable. I'd probably say half way between a floor screed and brickie a muck. No need for any admix type stuff.
Now lay the first slab. Your lines will act as a guide. You need to use some initiative due to the riven nature.
You'll never get each side perfect with a line, if you choose to keep pulling lines all over the job just make sure your not pushing it up or too low. This is why you need a half decent fall with sandstone.
Basically as long as your within a couple of mm of the line it's good. Use a level to ensure that water runs off each slab and onto the next. This is the key to laying sandstone, you need to make sure the next slab you lay won't trap water. If it does re lay the first one. Once you have a small area down it gets easier, and you'll be able to pretty much mimic what you've already done.
Oh and within reason forget about the brickwork on your house, a common mistake is for people to follow it but often that brickwork isn't level, so your just laying the patio to some random level.
You need to hit a happy medium, one where water drains off and it looks right.
Dot and dab is pretty
, it's to do with moisture getting underneath and popping them in frosts. It will also sound hollow and also there's a real chance of the dabs showing through the stone so you'll have a nice extra free dab pattern on each slab 
that Sid I have seen them done and last ok. Dot and dab is certainly easier by a long shot. I wouldn't recomend it though.
Tbh one thing I will say and it isn't aimed at you but more other paving people, builders etc is that many years ago stone took a certain knowledge to lay properly, now due to cost of it all everyone's a stone expert. It is IMO hard to lay and do it right.
The reason are
It's got a lot of tolerance in joint sizes, it can be un caliberated which tbh doesn't matter as your laying each slab individually on wet muck but it doesn't help. The surface is riven to the extent of a level doesn't really tell you you've done it right.
Here's what I would do or actually do
Set up some very taught string lines around the perimeter, if it's not square just square off a general main area first, then you can work off that once you've got some down. obviously start at the house and set your falls. This line is your finished patio level.....give or take a few mm.
To pull lines properly you need to bang something into the ground, a bit of 2x2 or what I use is those large steel pins used for temporary barriers etc.
You need enough fall, I can't remember what the actual recomended fall are off the top of my head but paving expert is your friend.
You want a cement bed depth of approx 75mm. Any less it's too thin, (unless going over concrete) any more and it's going to make life more difficult.
Mix sharp sand and cement to 5:1 or 4:1 or even 6:1
It needs to be wet enough to stick the slabs but not so wet that when you lay one and tap it down it starts swimming. Too dry and it won't be very pliable. I'd probably say half way between a floor screed and brickie a muck. No need for any admix type stuff.
Now lay the first slab. Your lines will act as a guide. You need to use some initiative due to the riven nature.
You'll never get each side perfect with a line, if you choose to keep pulling lines all over the job just make sure your not pushing it up or too low. This is why you need a half decent fall with sandstone.
Basically as long as your within a couple of mm of the line it's good. Use a level to ensure that water runs off each slab and onto the next. This is the key to laying sandstone, you need to make sure the next slab you lay won't trap water. If it does re lay the first one. Once you have a small area down it gets easier, and you'll be able to pretty much mimic what you've already done.
Oh and within reason forget about the brickwork on your house, a common mistake is for people to follow it but often that brickwork isn't level, so your just laying the patio to some random level.
You need to hit a happy medium, one where water drains off and it looks right.
Dot and dab is pretty
, it's to do with moisture getting underneath and popping them in frosts. It will also sound hollow and also there's a real chance of the dabs showing through the stone so you'll have a nice extra free dab pattern on each slab that Sid I have seen them done and last ok. Dot and dab is certainly easier by a long shot. I wouldn't recomend it though.I've laid both calibrated and un-calibrated in my own garden, and the best advice I can give is to go back to the merchants and buy calibrated ones. I think I paid something like £10+vat for 3x2 sandstone slabs.
The uncalibrated ones are an absolute pita to lay on a full bed, and dot and dab is the work of pie-keys.
If you want to struggle on with what you have, "ripple" the bed a lot more than you are doing now, to give yourself a chance of levelling them. It's not really "correct", but it's about the only hope you've got.
The uncalibrated ones are an absolute pita to lay on a full bed, and dot and dab is the work of pie-keys.
If you want to struggle on with what you have, "ripple" the bed a lot more than you are doing now, to give yourself a chance of levelling them. It's not really "correct", but it's about the only hope you've got.
Enjoying this thread. I am about to pave my patio (10 by 5 metres), I've put a small wall at the lawn edge as I'm levelling out a bit of a drop, only two courses high laying flat.
I smashed up an old small concrete patio which was breaking up and I'm using this to fill in to level. The stone I've got is calibrated kandla grey, the big pieces are heavy but manageable, I'm only worried about knowing what pattern to lay.
Tonight is spreading out the hardcore and smashing it down as much as possible with vibrating plate before putting the mot down.
I've not used the vibrating plate before, I've got a medium duty one. I'll experiment later but how big can you go over the old bits of concrete, some of the pieces are quite large and would like to break them up with it but I won't if it's knacker the plate.
I smashed up an old small concrete patio which was breaking up and I'm using this to fill in to level. The stone I've got is calibrated kandla grey, the big pieces are heavy but manageable, I'm only worried about knowing what pattern to lay.
Tonight is spreading out the hardcore and smashing it down as much as possible with vibrating plate before putting the mot down.
I've not used the vibrating plate before, I've got a medium duty one. I'll experiment later but how big can you go over the old bits of concrete, some of the pieces are quite large and would like to break them up with it but I won't if it's knacker the plate.
You'll need to smash up the hardcore as much as possible with a club hammer or sledge hammer, then compact it.
With regard to a pattern just literally make it up and avoid cross joints. Bear in mind due to to slab size inconsistency you'll have to make a happy medium with joint sizes they won't be the same throughout.
That said I'm sure there will be patterns online you'll be able to follow which will make it easier.
With regard to a pattern just literally make it up and avoid cross joints. Bear in mind due to to slab size inconsistency you'll have to make a happy medium with joint sizes they won't be the same throughout.
That said I'm sure there will be patterns online you'll be able to follow which will make it easier.
m3jappa said:
You'll need to smash up the hardcore as much as possible with a club hammer or sledge hammer, then compact it.
With regard to a pattern just literally make it up and avoid cross joints. Bear in mind due to to slab size inconsistency you'll have to make a happy medium with joint sizes they won't be the same throughout.
That said I'm sure there will be patterns online you'll be able to follow which will make it easier.
I used to always find the 1x1 Indian sandstone slabs were the worst for being out of size. The 2x1, 2x2 and 2x3 slabs weren't as problematic.With regard to a pattern just literally make it up and avoid cross joints. Bear in mind due to to slab size inconsistency you'll have to make a happy medium with joint sizes they won't be the same throughout.
That said I'm sure there will be patterns online you'll be able to follow which will make it easier.
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